People can preserve healthy streams or restore them to healthy conditions.
- Preserving a natural riparian buffer stabilizes the stream banks and filters rainwater flowing into the stream.
- Preserving a tree canopy shades and cools stream waters and provides leaf litter to feed aquatic insects.
- Preserving a rocky substrate helps aerate the water and provides stable living spaces for aquatic insects and fish.
- Preserving a floodplain with pervious surfaces helps filter and hold rainwater as it soaks into the ground.
Actions by people can turn healthy streams in farming areas into unhealthy streams.
- Removing the riparian buffer causes bank erosion, fills the stream with mud and sediment, and warms up the water in the summer.
- Neglecting to install fences and alternative water sources to keep livestock out of streams allows them to erode the stream banks and introduce fecal waste that contaminates the water.